The functions module now applies time-step restrictions from the
functions that are running, rather than from the sub-solver. The
sub-solver only exists to be constructed so that its data is available
to the functions. It should not affect the solution process in any way.
A cloud's volume fraction is now generated with parcelCloud::alpha, and
the mass fraction with parcelCloud::Y. This is consistent with the rest
of OpenFOAM.
requiring all parts of the moving phase solution algorithm to loop and operate
on the moving phases only making the code easier to understand and maintain.
The central coefficient part of the virtual-mass phase acceleration matrix is
now included in the phase velocity transport central coefficient + drag matrix
so that the all the phase contributions to each phase momentum equation are
handled implicitly and consistently without lagging contribution from the other
phases in either the pressure equation or phase momentum correctors.
This improves the conditioning of the pressure equation and convergence rate of
bubbly-flow cases.
Population balance size-group fraction 'f<index>.<phase>' fields are now
read from an 'fDefault.<phase>' field if they are not provided
explicitly. This is the same process as is applied to species fractions
or fvDOM rays. The sum-of-fs field 'f.<phase>' is no longer required.
The value of a fraction field and its boundary conditions must now be
specified in the corresponding field file. Value entries are no longer
given in the size group dictionaries in the constant/phaseProperties
file, and an error message will be generated if a value entry is found.
The fraction fields are now numbered programatically, rather than being
named. So, the size-group dictionaries do not require a name any more.
All of the above is also true for any 'kappa<index>.<phase>' fields that
are constructed and solved for as part of a fractal shape model.
The following is an example of a specification of a population balance
with two phases in it:
populationBalances (bubbles);
air1
{
type pureIsothermalPhaseModel;
diameterModel velocityGroup;
velocityGroupCoeffs
{
populationBalance bubbles;
shapeModel spherical;
sizeGroups
(
{ dSph 1e-3; } // Size-group #0: Fraction field f0.air1
{ dSph 2e-3; } // ...
{ dSph 3e-3; }
{ dSph 4e-3; }
{ dSph 5e-3; }
);
}
residualAlpha 1e-6;
}
air2
{
type pureIsothermalPhaseModel;
diameterModel velocityGroup;
velocityGroupCoeffs
{
populationBalance bubbles;
shapeModel spherical;
sizeGroups
(
{ dSph 6e-3; } // Size-group #5: Fraction field f5.air2
{ dSph 7e-3; } // ...
{ dSph 8e-3; }
{ dSph 9e-3; }
{ dSph 10e-3; }
{ dSph 11e-3; }
{ dSph 12e-3; }
);
}
residualAlpha 1e-6;
}
Previously a fraction field was constructed automatically using the
boundary condition types from the sum-of-fs field, and the value of both
the internal and boundary field was then overridden by the value setting
provided for the size-group. This procedure doesn't generalise to
boundary conditions other than basic types that store no additional
data, like zeroGradient and fixedValue. More complex boundary conditions
such as inletOutlet and uniformFixedValue are incompatible with this
approach.
This is arguably less convenient than the previous specification, where
the sizes and fractions appeared together in a table-like list in the
sizeGroups entry. In the event that a substantial proportion of the
size-groups have a non-zero initial fraction, writing out all the field
files manually is extremely tedious. To mitigate this somewhat, a
packaged function has been added to initialise the fields given a file
containing a size distribution (see the pipeBend tutorial for an example
of its usage). This function has the same limitations as the previous
code in that it requires all boundary conditions to be default
constructable.
Ultimately, the "correct" fix for the issue of how to set the boundary
conditions conveniently is to create customised inlet-outlet boundary
conditions that determine their field's position within the population
balance and evaluate a distribution to determine the appropriate inlet
value. This work is pending funding.
Now with the addition of the optional dependenciesModified() function classes
which depend on other classes which are re-read from file when modified are also
automatically updated via their read() function called by
objectRegistry::readModifiedObjects.
This significantly simplifies the update of the solutionControls and modular
solvers when either the controlDict or fvSolution dictionaries are modified at
run-time.
The momentum equation central coefficient and drag matrix is formulated,
inverted and used to eliminate the drag terms from each of the phase momentum
equations which are combined for formulate a drag-implicit pressure equation.
This eliminates the lagged drag terms from the previous formulation which
significantly improves convergence for small particle and Euler-VoF high-drag
cases.
It would also be possible to refactor the virtual-mass terms and include the
central coefficients of the phase acceleration terms in the drag matrix before
inversion to further improve the implicitness of the phase momentum-pressure
coupling for bubbly flows. This work is pending funding.
to specify the path name of the output dictionary to which the expanded and/or
changed dictionary is written.
Usage: foamDictionary [OPTIONS] <dictionary file>
options:
-add <value> Add a new entry
-case <dir> specify alternate case directory, default is the cwd
-dict Set, add or merge entry from a dictionary.
-diff <dict> Write differences with respect to the specified dictionary
-entry <name> report/select the named entry
-expand Read the specified dictionary file and expand the macros
etc.
-fileHandler <handler>
override the fileHandler
-hostRoots <((host1 dir1) .. (hostN dirN))>
slave root directories (per host) for distributed running
-includes List the #include/#includeIfPresent files to standard output
-keywords list keywords
-libs '("lib1.so" ... "libN.so")'
pre-load libraries
-merge <value> Merge entry
-noFunctionObjects
do not execute functionObjects
-output <path name>
Path name of the output dictionary
-parallel run in parallel
-remove Remove the entry.
-roots <(dir1 .. dirN)>
slave root directories for distributed running
-set <value> Set entry value, add new entry or apply list of
substitutions
-value Print entry value
-writePrecision <label>
Write with the specified precision
-srcDoc display source code in browser
-doc display application documentation in browser
-help print the usage
manipulates dictionaries
Now if the -case option is specified the dictionary path provided is treated as
relative to the case path, e.g.
foamDictionary -expand -case shockFluid/shockTube system/controlDict
The functionality necessary to write in a different unit set has been
removed. This was excessivelty complex, never used in practice, and of
little practical usage. Output numeric data, in general, is not designed
to be conveniently user-readable, so it is not important what unit
system it is written in.
DecomposePar and reconstructPar now interleave the processing of
multiple regions. This means that with the -allRegions option, the
earlier times are completed in their entirety before later times are
considered. It also lets regions to access each other during
decomposition and reconstruction, which will be important for
non-conformal region interfaces.
To aid interpretation of the log, region prefixing is now used by both
utilities in the same way as is done by foamMultiRun.
DecomposePar has been overhauled so that it matches reconstructPar much
more closely, both in terms of output and of iteration sequence. All
meshes and addressing are loaded simultaneously and each field is
considered in turn. Previously, all the fields were loaded, and each
process and addressing set was considered in turn. This new strategy
optimises memory usage for cases with lots of fields.
When the flow is stationary (e.g., at the beginning of a run) the
rDeltaT calculation now requires a maxDeltaT setting in the PIMPLE
sub-section of the fvSolution dictionary. This prevents floating point
errors associated with rDeltaT approaching zero.
The phase velocity mean adjustment was introduced for consistency with phase
flux mean adjustment which is necessary to ensure the mean flux divergence is
preserved. However for systems with very high drag it has proved preferable to
not adjust the velocity of the phases to conserve momentum rather than ensure
consistency with the fluxes.
The old fluid-specific rhoThermo has been split into a non-fluid
specific part which is still called rhoThermo, and a fluid-specific part
called rhoFluidThermo. The rhoThermo interface has been added to the
solidThermo model. This permits models and solvers that access the
density to operate on both solid and fluid thermophysical models.
Mixture classes (e.g., pureMixtrure, coefficientMulticomponentMixture),
now have no fvMesh or volScalarField dependence. They operate on
primitive values only. All the fvMesh-dependent functionality has been
moved into the base thermodynamic classes. The 'composition()' access
function has been removed from multi-component thermo models. Functions
that were once provided by composition base classes such as
basicSpecieMixture and basicCombustionMixture are now implemented
directly in the relevant multi-component thermo base class.
Application
engineCompRatio
Description
Calculate the compression ratio of the engine combustion chamber
If the combustion chamber is not the entire mesh a \c cellSet or
\c cellZone name of the cells in the combustion chamber can be provided.
Usage
\b engineCompRatio [OPTION]
- \par -cellSet \<name\>
Specify the cellSet name of the combustion chamber
- \par -cellZone zoneName
Specify the cellZone name of the combustion chamber
at Function1s of time.
Underlying this new functionObject is a generalisation of the handling of the
maximum time-step in the modular solvers to allow complex user-specification of
the maximum time-step used in a simulation, not just the time-dependency
provided by fluidMaxDeltaT but functions of anything in the simulation by
creating a specialised functionObject in which the maxDeltaT function is
defined.
The chemical and combustion time-scale functionObjects adjustTimeStepToChemistry
and adjustTimeStepToCombustion have been updated and simplified using the above
mechanism.
and make '-explicitFeatures' the option to use explicitFeatures. When implicitFeatures
is used, a surfaceFeaturesDict file is not written out to the system directory
Description
Calculates and applies the random OU (Ornstein-Uhlenbeck) process force to
the momentum equation for direct numerical simulation of boxes of isotropic
turbulence.
The energy spectrum is calculated and written at write-times which is
particularly useful to test and compare LES SGS models.
Note
This random OU process force uses a FFT to generate the force field which
is not currently parallelised. Also the mesh the FFT is applied to must
be isotropic and have a power of 2 cells in each direction.
Usage
Example usage:
\verbatim
OUForce
{
type OUForce;
libs ("librandomProcesses.so");
sigma 0.090295;
alpha 0.81532;
kUpper 10;
kLower 7;
}
\endverbatim
The tutorials/incompressibleFluid/boxTurb16 tutorial case is an updated version
of the original tutorials/legacy/incompressible/dnsFoam/boxTurb16 case,
demonstrating the use of the OUForce fvModel with the incompressibleFluid solver
module to replicate the behaviour of the legacy dnsFoam solver application.
for the multiphaseEuler solver module, replacing the more specific
uniformFixedMultiphaseHeatFluxFvPatchScalarField as it provide equivalent
functionality if the heat-flux q is specified.
multiphaseExternalTemperatureFvPatchScalarField is derived from the refactored
and generalised externalTemperatureFvPatchScalarField, overriding the
getKappa member function to provide the multiphase equivalents of kappa and
other heat transfer properties. All controls for
multiphaseExternalTemperatureFvPatchScalarField are the same as for
externalTemperatureFvPatchScalarField:
Class
Foam::externalTemperatureFvPatchScalarField
Description
This boundary condition applies a heat flux condition to temperature
on an external wall. Heat flux can be specified in the following ways:
- Fixed power: requires \c Q
- Fixed heat flux: requires \c q
- Fixed heat transfer coefficient: requires \c h and \c Ta
where:
\vartable
Q | Power Function1 of time [W]
q | Heat flux Function1 of time [W/m^2]
h | Heat transfer coefficient Function1 of time [W/m^2/K]
Ta | Ambient temperature Function1 of time [K]
\endvartable
Only one of \c Q or \c q may be specified, if \c h and \c Ta are also
specified the corresponding heat-flux is added.
If the heat transfer coefficient \c h is specified an optional thin thermal
layer resistances can also be specified through thicknessLayers and
kappaLayers entries.
The patch thermal conductivity \c kappa is obtained from the region
thermophysicalTransportModel so that this boundary condition can be applied
directly to either fluid or solid regions.
Usage
\table
Property | Description | Required | Default value
Q | Power [W] | no |
q | Heat flux [W/m^2] | no |
h | Heat transfer coefficient [W/m^2/K] | no |
Ta | Ambient temperature [K] | if h is given |
thicknessLayers | Layer thicknesses [m] | no |
kappaLayers | Layer thermal conductivities [W/m/K] | no |
relaxation | Relaxation for the wall temperature | no | 1
emissivity | Surface emissivity for radiative flux to ambient | no | 0
qr | Name of the radiative field | no | none
qrRelaxation | Relaxation factor for radiative field | no | 1
\endtable
Example of the boundary condition specification:
\verbatim
<patchName>
{
type externalTemperature;
Ta constant 300.0;
h uniform 10.0;
thicknessLayers (0.1 0.2 0.3 0.4);
kappaLayers (1 2 3 4);
value $internalField;
}
\endverbatim
See also
Foam::mixedFvPatchScalarField
Foam::Function1
